Technical Field
The present invention relates to a positional information transmission system, a positional information transmitter, and a positional information transmitting method.
Background Art
Recently, starting with car navigation systems, portable information devices such as smartphones and tablet computers include a Global Positioning System (GPS) function. In the GPS, multiple GPS satellites that orbit around the earth transmit wireless signals that indicate time, and receivers receive those signals. Subsequently, distance between the receiver and the satellites is calculated based on difference between time when the satellites transmit the wireless signals and time when the communication device receives the wireless signals, and a position on the earth is specified based on the calculation result. By using the GPS function described above, it is possible to check a current position on a map and utilize a routing guidance by user operation using the portable information devices.
However, in the GPS that receives radio wave from the satellites described above, since the wireless signal strength is weak in areas such as underground malls and interiors, it is difficult to utilize the services such as displaying the current position and routing guidance described above in some cases.
A technology called Indoor Messaging System (IMES) as an indoor positioning technology that enables to utilize the positional information even in areas such as the underground malls is known. In the IMES, indoor transmitters are installed, and the indoor transmitters transmit the positional information of the transmitter as radio wave. The receivers receive the positional information of the indoor transmitters, and it is possible to acquire the position of the receiver. Conventionally, technologies that utilize the IMES are known.
Other than that, indoor positioning technologies such as a technology that transmits beacon information from access points in a wireless local area network (LAN) and a technology that transmits beacon on a Bluetooth Low Energy (BLE) signal are known. In addition, regarding the routing guidance described above, a system that registers information such as a train route map and a train timetable in Radio Frequency Identification (RFID) tags, installs the RFID tags, and enables users to scan the information such as the train route map and the train timetable by holding a reader on the RFID tag.